Centrelink, Medicare and Child Support services experienced some disruptions nationwide on Friday as the union engaged in further industrial action.
The Department of Human Services and the Community and Public Sector Union are currently engaged in Fair Work Commission negotiations after three years of stalled enterprise bargaining.
CPSU members, including hundreds of Latrobe Valley call centre workers, had the option of rolling stoppages from 1.30pm to 8.30pm Friday.
DHS general manager Hank Jongen expressed disappointment action was taking place while discussions continued with the FWC.
"The industrial action will not change the department's position in terms of negotiations for a new enterprise agreement," a DHS statement said.
The department said its most recent offer maintained "virtually all existing staff entitlements, including all its family friendly entitlements" and offered "staff a pay rise that is in line with community standards".
CPSU deputy national president Lisa Newman hit back, saying the offer was far from equitable and the union had no choice but to continue to take planned action.
"This agreement-making process has been entrained for three years and the department is still pressing us to accept cuts for a record low pay offer of six per cent over a three-year proposed agreement with no compensation for the three-year wage freeze that DHS workers have suffered, which has in effect driven their real wages backward," Ms Newman said.
"After three years we've been extremely patient but that patience has worn out; if the department wants to stop industrial action they need to take the cuts off the table."
On Friday Ms Newman said Latrobe Valley workers were likely to engage in the action.
She said there were about 400 casual workers in Latrobe Valley call centres in positions the CPSU believes should be predominantly permanent.
"The Latrobe Valley has been particularly affected because it's been bleeding permanent jobs out of the call centre," she said.
"Not only is that an issue in relation to the next agreement and protecting people's job security, it's also having an impact on services the community can access.
"It's absolutely shocking and they're doing work that is permanent, the only thing that is not permanent is the nature of their employment."
Negotiations between the parties and the FWC are ongoing.